thanks @robkk. makes sense, think it’s not in the codex.
I’ve got a navigation menu with links to specific topics (made with the backend’s customizer). Would like to add the correct count to each navigation menu link.

Suppose that it would be easier to create a new custom navigation menu via functions as it’s not that easy to target the specific locations, right?

But in case you have an idea how to target those customizer created links to add a count, this surely would help for many other things as well.